Seven Asteroids Studied from Modra Observatory in the Course of Binary Asteroid Photometric Campaign

We report lightcurves for five asteroids from the inner main belt—(1703) Barry, (2590) Mourão, (4022) Nonna, (5171) Augustesen, (23031) 1999 XX₇—and for two near-Earth asteroids—(100004) 1983 VA, (144922) 2005 CK₃₈—obtained at Modra Observatory as a part of binary asteroid photometric campaign. Estimated synodic rotational periods and amplitudes of their composite lightcurves were as follows: 107.1 ± 0.5 h, 0.5 mag for (1703) Barry; 15.59 ± 0.01 h, 0.49 mag for (2590) Mourão; 2.5877 ± 0.0005 h, 0.08 mag for (4022) Nonna; 474 ± 10 h, 0.8 mag for (5171) Augustesen; 3.075 ± 0.001 h, 0.43 mag for (23031) 1999 XX₇; 3.1643 ± 0.0009 h, 0.11 mag for (100004) 1983 VA; 4.7894 ± 0.0005 h, 0.27 mag for (144922) 2005 CK₃₈. The slow rotator (5171) Augustesen and possibly also (1703) Barry appear to be tumblers, though their precession periods can not be estimated from the available data.     

Physical parameters of the atmosphere of Venus from Venera 15 and 16 missions

The following physical parameters have been computed for the atmosphere of Venus between 65 and 90 km, by intervals of 1 km. (1) Pressure, (2) Density, (3) Speed of sound, (4) Number density, (5) Density scale, (6) Pressure scale, (7) Collisional frequency, (8) Mean particle velocity (9) Mean free path, (10) Columnar mass, (11) Viscosity. For these calculations we have used the temperature altitude measurements of Venera 15 and 16 at 52 °N and 72 °N latitudes, the night and 70 °N and 72 °N latitudes the day.     

Near-infrared spectroscopy of 3:1 Kirkwood Gap Asteroids: (3760) Poutanen and (974) Lioba

A mineralogical assessment of 3:1 Kirkwood Gap Asteroids (3760) Poutanen and (974) Lioba, has been carried out from spectral data obtained May 21, 2008 (974) and May 25, 2009 (3760) UT using the NASA Infrared Telescope Facility. Results indicate (3760) Poutanen as a spinel-bearing asteroid. The spinel contained within this asteroid appears to be embedded in calcium aluminum inclusions (CAIs) much like that of the CV3 chondrite Allende. The preservation of the CAIs implies a lack of igneous processing and places further constraints on the heating that occurred within the early Solar System. This analysis suggests (3760) Poutanen originated in the general formation zone of the CV3 meteorites, but in a sub-region depleted in iron-rich matrix material and enriched in pyroxene-bearing clasts. Analysis of (974) Lioba indicates it is an S(IV) asteroid with a surface silicate assemblage consisting of olivine and orthopyroxene, (Fs_21(±5)Wo_8(±3)), consistent with measured band centers, (0.96 ± 0.01 μm; 1.95 ± 0.02 μm), and the band area ratio (0.59 ± 0.15). The location, delivery efficiency ((24.5%) Farinella, P., Gunczi, R., Froeschlé, Ch., Froeschlé, C. [1993]. Icarus 101, 174-187), calculated mineralogy, and BAR strongly suggest (974) Lioba is a plausible parent body for the LL- or L-ordinary chondrites.     

Coeval argon‐40/argon‐39 ages of moldavites from the Bohemian and Lusatian strewn fields

Abstract— ⁴⁰Ar/³⁹Ar ages of four tektites (moldavites) from southern Bohemia (near ?eské Budějovice, Czech Republic) and a tektite from Lusatia (near Dresden, Germany) have been determined by 11 step‐degassing experiments. The purpose of the study was to enlarge the ⁴⁰Ar/³⁹Ar data base of moldavites and to check the age relations of the Bohemian and Lusatian samples. The mean plateau‐age of the Bohemian samples, which range from 14.42 to 14.70 Ma, is 14.50 ± 0.16 (0.42) (2σ) Ma (errors in parentheses include age error and uncertainty of standard monitor age). The plateau age of the Lusatian sample of 14.38 ± 0.26 (0.44) (2σ) Ma confirms the previously published ⁴⁰Ar/³⁹Ar age of 14.52 ± 0.08 (0.40) (2σ) Ma, and demonstrates that the fall of Lusatian and Bohemian tektites were contemporaneous. Because of their geochemistry and their ages there is no doubt that the Lusatian tektites are moldavites. Accepting that moldavites are ejecta from the Nördlinger Ries impact, the new ages also date the impact event. This age is slightly younger (about 0.2–0.3 Ma) than the age suggested by earlier K‐Ar determinations.     

Relationship between the geomagnetic Dst(min) and the interplanetary Bz(min) during cycle 23

In cycle 23 for geomagnetic storms of ?Dst(min) >50 nT, the plot of ?Dst(min) versus ?Bz(min) for the low ?Bz(min) range 0–10 nT showed erratic variation in Dst(min), (correlation 0.19). Even for ?Bz(min) range 10–20 nT, ?Dst(min) values had considerable scatter (correlation 0.57). For ?Bz(min).>20 nT, the relationship was good (correlation 0.82). For the whole range ?Bz(min) 0–50 nT, the correlation was high (0.88). Thus, if ?Bz(min) is very large (～20 nT), large ?Dst(min) occurs but in a wide range of 100–500 nT.     

Do Long-Lived Features Really Exist in the Solar Photosphere? II. Contrast of Time-Averaged Granulation Images

The decrease in the rms contrast of time-averaged images with the averaging time is compared between four data sets: (1) a series of solar granulation images recorded at La Palma in 1993, (2) a series of artificial granulation images obtained in numerical simulations by Rieutord et al. (Nuovo Cimento 25, 523, 2002), (3) a similar series computed by Steffen and his colleagues (see Wedemeyer et al. in Astron. Astrophys. 44, 1121, 2004), (4) a random field with some parameters typical of the granulation, constructed by Rast (Astron. Astrophys. 392, L13, 2002). In addition, (5) a sequence of images was obtained from real granulation images by using a temporal and spatial shuffling procedure, and the contrast of the average of n images from this sequence as a function of n is analysed. The series (1) of real granulation images exhibits a considerably slower contrast decrease than do both the series (3) of simulated granulation images and the series (4) of random fields. Starting from some relatively short averaging times t, the behaviour of the contrast in series (3) and (4) resembles the t ^−1/2 statistical law, whereas the shuffled series (5) obeys the n ^−1/2 law from n=2 on. Series (2) demonstrates a peculiarly slow decline of contrast, which could be attributed to particular properties of the boundary conditions used in the simulations. Comparisons between the analysed contrast-variation laws indicate quite definitely that the brightness field of solar granulation contains a long-lived component, which could be associated with locally persistent dark intergranular holes and/or with the presence of quasi-regular structures. The suggestion that the random field (4) successfully reproduces the contrast-variation law for the real granulation (Rast in Astron. Astrophys. 392, L13, 2002) can be dismissed.     

Periodic motions around pulsating stars

The periodic motion of a test particle (dust, grain, or a larger body) around a pulsating star with a luminosity oscillation of small amplitude (featured by a small parameterB) is being studied. The perturbations of all orbital elements are determined to first order inB, by using Delaunay-type canonical variables and a method whose bases were put forth by von Zeipel. According to the value of the ratio oscillation frequency/dynamic frequency, three possible situations are pointed out: nonresonant (NR), quasi-resonant (QR), and resonant (R). The solution of motion equations shows that only in the (QR) and (R) cases there are orbital parameters (argument of periastron and mean anomaly) affected by secular perturbations. These solutions (which indicate a secularly stable motion in a first approximation) are valid over prediction times of orderB ^–1 in the (NR) case andB ^–1/2 in the (QR) and (R) cases. The theory may be applied to various astronomical situations.     

CCD-photometry and pole coordinates for eight asteroids

The long time photometric observations were carried out for eight asteroids: (122) Gerda, (153) Hilda, (190) Ismene, (221) Eos, (411) Xanthe, (679) Pax, (700) Auravictrix, (787) Moskva. New rotation periods have been determined for the asteroids (153) Hilda (5.959 h) and (411) Xanthe (11.408 h), and known rotation periods for some of the others have been confirmed. Using our data and others data we have estimated new pole coordinates for the observed asteroids.     

Silica-merrihueite/roedderite-bearing chondrules and clasts in ordinary chondrites: New occurrences and possible origin

Abstract Merrihueite (K,Na)₂(Fe, Mg)₅Si₁₂O₃₀ (na < 0.5, fe > 0.5, where na = Na/(Na + K), fe = Fe/(Fe + Mg) in atomic ratio) is a rare mineral described only in several chondrules and irregularly-shaped fragments in the Mezö-Madaras L3 chondrite (Dodd et al., 1965; Wood and Holmberg, 1994). Roedderite (Na,K)₂(Mg, Fe)₅Si₁₂O₃₀ (na > 0.5, fe < 0.5) has been found only in enstatite chondrites and in the reduced, subchondritic silicate inclusions in IAB irons (Fuchs, 1966; Rambaldi et al., 1984; Olsen, 1967). We describe silica-roedderite-bearing clasts in L/LL3.5 ALHA77011 and LL3.7 ALHA77278, a silica-roedderite-bearing chondrule in L3 Mezö-Madaras, and a silica-merrihueite-bearing chondrule in L/LL3.5 ALHA77115. The findings of merrihueite and roedderite in ALHA77011, ALHA77115, ALHA77278 and Mezö-Madaras fill the compositional gap between previously described roedderite in enstatite chondrites and silicate inclusions in IAB irons and merrihueite in Mezö-Madaras, suggesting that there is a complete solid solution of roedderite and merrihueite in meteorites. We infer that the silica- and merrihueite/roedderite-bearing chondrules and clasts experienced a complex formational history including: (a) fractional condensation in the solar nebula that produced Si-rich and Al-poor precursors, (b) melting of fractionated nebular solids resulting in the formation of silica-pyroxene chondrules, (c) in some cases, fragmentation in the nebula or on a parent body, (d) reaction of silica with alkali-rich gas that formed merrihueite/roedderite on a parent body, (e) formation of fayalitic olivine and ferrosilite-rich pyroxene due to reaction of silica with oxidized Fe on a parent body, and (f) minor thermal metamorphism, possibly generated by impacts.     

Mineralogical characterization of near-Earth Asteroid (1036) Ganymed

We present a mineralogical assessment of near-Earth Asteroid, (1036) Ganymed, using data obtained May 18, 2006 UT combined with 24 Color Asteroid Survey data to cover the spectral interval of 0.3-2.45 μm. Results of the analysis indicate (1036) Ganymed is an S (VI) asteroid with a surface silicate assemblage consisting primarily of orthopyroxene, (Fs_23(±5)Wo_3(±3)), consistent with calculated band centers and band area ratios (BAR). (1036) Ganymed appears to be once part of a large mesosiderite containing howardite, eucrite, and diogenite (HED) pyroxenes mixed with metal that was broken apart and dispersed. The calculated composition of the average pyroxenes in the surface material of (1036) Ganymed is consistent with mesosiderite pyroxenes, in particular the diogenites. A second possibility could be (1036) Ganymed is not yet represented in the meteorite collection. Our investigation has confirmed Ganymed is not a parent body of the ordinary chondrites and is not genetically related to (433) Eros.     

The CR chondrite clan: Implications for early solar system processes

Abstract— In this paper, we review the mineralogy and chemistry of calcium‐aluminum‐rich inclusions (CAIs), chondrules, FeNi‐metal, and fine‐grained materials of the CR chondrite clan, including CR, CH, and the metal‐rich CB chondrites Queen Alexandra Range 94411, Hammadah al Hamra 237, Bencubbin, Gujba, and Weatherford. The members of the CR chondrite clan are among the most pristine early solar system materials, which largely escaped thermal processing in an asteroidal setting (Bencubbin, Weatherford, and Gujba may be exceptions) and provide important constraints on the solar nebula models. These constraints include (1) multiplicity of CAI formation; (2) formation of CAIs and chondrules in spatially separated nebular regions; (3) formation of CAIs in gaseous reservoir(s) having ¹⁶O‐rich isotopic compositions; chondrules appear to have formed in the presence of ¹⁶O‐poor nebular gas; (4) isolation of CAIs and chondrules from nebular gas at various ambient temperatures; (5) heterogeneous distribution of ²⁶Al in the solar nebula; and (6) absence of matrix material in the regions of CAI and chondrule formation.     

Radio emission of fast cosmic ions

It is usually assumed that the ions of cosmic rays contribute nothing to the observable electromagnetic radiation. However, this is true only when these ions are moving in a vacuum or a quiet (nonturbulent) plasma. In the case of fast ions in a turbulent plasma, there is an effective nonlinear mechanism of radiation which is discussed in this paper. The fast ion (relativistic or nonrelativistic) moving in the plasma creates a polarization cloud around itself which also moves with the particles. The turbulent plasma waves may scatter on the moving electric field of this polarization cloud. In the process of this scattering an electromagnetic wave with frequency (2.7) is generated. Let ₁ and k₁ be the frequency and wave vector of turbulent plasma waves,V is the velocity of the ion, and is the angle between the wave vector of electromagnetic radiation and the direction of the ion velocity. The method of calculating the probability of the conversion of plasma waves (k₁) into electromagnetic waves (k) by scattering on an ion with velocityV is described in detal in Section 2 (Equation (2.14)).The spectral coefficients of spontaneous radiation in the case of scattering of plasma waves on polarization clouds created by fast nonrelativistic ions are given in (3.6) for an ion energy distribution function (3.4) and in (3.8) for more general evaluations. The Equations (3.9)–(3.13) describe the spectral coefficients of spontaneous emission for different modes of plasma turbulence (Langmuir (3.9), electron cyclotron in a weak (3.10) or strong (3.11) magnetic field and ion acoustic (3.12)–(3.13) waves). The coefficients of reabsorption or induced emission are given by Equations (3.14) and (3.16)–(3.19). There is a maser effect in the case of scattering of plasma waves on a stream of ions. The effective temperature of the spontaneous emission is given by Equation (3.15). The spectral coefficients of radiation due to scattering of plasma waves on relativistic ions are calculated in the same manner (Equations (4.14)–(4.15)). The total energy loss due to this radiation is given in Equations (4.23)–(4.25). The coefficients of induced emission are given in (4.26)–(4.28).The results are discussed in Section 5. It is shown that the loss of energy by nonlinear plasma radiation is much smaller than the ionization loss. However, the coefficients of synchrotron radiation of electrons and nonlinear radiation of ions under cosmic conditions may be comparable in the case of a weak magnetic field and fairly low frequencies (5.5)–(5.6). Usually the spectrum of nonlinear plasma radiation is steeper than in the case of synchroton radiation. Equation (5.10) gives the condition for nonlinear radiation to prevail over thermal radiation.Translated by D. F. Smith.     

The Near-Earth Objects Follow-Up Program

We present the results of photometric observations of the near-Earth asteroids (1943) Anteros, (2102) Tantalus, (2212) Hephaistos, (3199) Nefertiti, (5751) Zao = 1992 AC, (6322) 1991 CQ, (7474) 1992 TC, and 1989 VA made between 1982 and 1995. Synodic rotation periods in the range from 2.39 to 5.54 hr were derived for five of them, and we were able to place lower limits on periods of (2212) and (5751)—both > 20 hr. Only the period of the low amplitude case of (1943) was not constrained. The most interesting results were obtained for the following objects: (2102), a fast rotator (period 2.39 hr) in an extremely inclined orbit (i≈ 64°); (2212), a low amplitude slow rotator considered as an inactive cometary nucleus candidate; (3199), which showed similar lightcurves at quite different positions of the phase angle bisector, constraining its rotational pole; and 1989 VA, an unusual Aten asteroid with a rotation period of 2.51 hr and a relatively large amplitude. Overall, these results continue the pattern that NEO spins exhibit a bimodal distribution of spin rates.     

Period-luminosities relation of classical Cepheids

A new PL-relation (10) — Figure 2 for the Cepheids in the Galaxy, the Magellanic Clouds and M31 has been constructed. On deriving this relation both the period-radius (3) and period-colour relations (7), (8) and (9) are essentially used. The PC-relation (7) determined after the colours of 88 galactic cepheids (Table I), which are obtained from the colour-spectrum relation (6) — Figure 1, common for Cepheids and non-variable supergiants, are used also for the M31 Cepheids, whereas (8) and (9) are for the Large and Small MC Cepheids, respectively, all three PC-relations having a common slope. The comparison of the relations (8) and (9) with (7) shows that the LMC and SMC Cepheids are bluer than the galactic ones with 0^m.04 and 0^m.19, respectively, probably because of their metal-poor abundance. The places of thes-Cepheids in Figure 2 show that these Cepheids possess a dissimilar PL-relation with a different slope. The reason for such a difference is that thes-Cepheids are first harmonic pulsators. The distance moduli of the three galaxies under discussion are obtained from the PL-relation (10). The colour-coefficient of period-colour-luminosity-relation is briefly discussed. The general conclusion based on a comparison of the PL-relation in the present paper with those by other authors (Table V) is that our PL-relation differs in the zero-point by less than 0^m.2; therefore, the manner of constructing the PL-relation by means of PR and PC-relations is reasonable and useful.     

Micro‐X‐ray diffraction assessment of shock stage in enstatite chondrites

Abstract– A new method for assessing the shock stage of enstatite chondrites has been developed, using in situ micro‐X‐ray diffraction (μXRD) to measure the full width at half maximum (FWHM_χ) of peak intensity distributed along the direction of the Debye rings, or chi angle (χ), corresponding to individual lattice reflections in two‐dimensional XRD patterns. This μXRD technique differs from previous XRD shock characterization methods: it does not require single crystals or powders. In situ μXRD has been applied to polished thin sections and whole‐rock meteorite samples. Three frequently observed orthoenstatite reflections were measured: (020), (610), and (131); these were selected as they did not overlap with diffraction lines from other phases. Enstatite chondrites are commonly fine grained, stained or darkened by weathering, shock‐induced oxidation, and metal/sulfide inclusions; furthermore, most E chondrites have little olivine or plagioclase. These characteristics inhibit transmitted‐light petrography, nevertheless, shock stages have been assigned MacAlpine Hills (MAC) 02837 (EL3) S3, Pecora Escarpment (PCA) 91020 (EL3) S5, MAC 02747 (EL4) S4, Thiel Mountains (TIL) 91714 (EL5) S2, Allan Hills (ALHA) 81021 (EL6) S2, Elephant Moraine (EET) 87746 (EH3) S3, Meteorite Hills (MET) 00783 (EH4) S4, EET 96135 (EH4–5) S2, Lewis Cliff (LEW) 88180 (EH5) S2, Queen Alexandra Range (QUE) 94204 (EH7) S2, LaPaz Icefield (LAP) 02225 (EH impact melt) S1; for the six with published shock stages, there is agreement with the published classification. FWHM_χ plotted against petrographic shock stage demonstrates positive linear correlation. FWHM_χ ranges corresponding to shock stages were assigned as follows: S1 < 0.7°, S2 = 0.7–1.2°, S3 = 1.2–2.3°, S4 = 2.3–3.5°, S5 > 3.5°, S6—not measured. Slabs of Abee (EH impact‐melt breccia), and Northwest Africa (NWA) 2212 (EL6) were examined using μXRD alone; FWHM_χ values place both in the S2 range, consistent with literature values. Micro‐XRD analysis may be applicable to other shocked orthopyroxene‐bearing rocks.     

A re-determination of the boundaries of the cusp

Ariel 4 data (Goodallet al., 1973) of February 4 to May 5 1972 have been used to investigate the cusp boundaries. Data with the same local time (LT) and magnetic local time (MLT) around noontime and at high invariant latitudes (INL) have been used to represent the cusp area. (1) For noontime hours (MLT=1200 and LT=1200) high electron density values are observed. (2) the boundary towards the equator of the high density region starts at 76°–77° INL and the poleward boundary is at about 82° INL. Therefore, high electron densities are observed along an INL interval of 5°–6° at the Ariel 4 heights of 500–600 km, agreeing with other investigations.     

Gyldén Model: The Slowly Changing Equivalent Gravitational Parameter

In the Gyldén problem, the case of slowly changing equivalent gravitational parameter (e.g.p.) is studied. Assuming the following law for the variation of the e.g.p.: μ (t) = μ₀+ εμ (εt), ε< μ₀, we obtained a) a O(ε⁴ T⁴)-approximation of the solution, on a shortened time scale (0,T), with T of order o(ε^-1),for the general case (i.e. the support function μ is O(1)-valued and admits an expansion in power series of its argument), and b) a O(ε²)-approximation of the solution, on a natural timescale of order O(1/ε), for the case of a bounded variation rate (i.e. the support function μ and its derivative are both O(1)-valued). For the study of the first problem we introduced a type of Lissajous variables and used the Lie-Hori normalization scheme; for the second problem we used the Delaunay variables and applied the von Zeipel method for approximate integration. The physical interpretation of the results is in both cases the same: within the corresponding limits of approximation, the variation of e.g.p. (i) has no effect on the size of the osculating ellipse, (ii) it sets the pericenter in slow rotation and (iii) it introduces a secular variation in the longitudes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Density,porosity, and magnetic susceptibility of carbonaceous chondrites

Abstract– We report physical properties (bulk and grain density, magnetic susceptibility, and porosity) measured using nondestructive and noncontaminating methods for 195 stones from 63 carbonaceous chondrites. Grain densities over the whole population average 3.44 g cm^?3, ranging from 2.42 g cm^?3 (CI1 Orgueil) to 5.66 g cm^?3 (CB Bencubbin). Magnetic susceptibilities (in log units of 10^?9 m³ kg^?1) averaged log χ = 4.22, ranging from 3.23 (CV3 Axtell) to 5.79 (CB Bencubbin). Porosities averaged 17%, ranging from 0 (for a number of meteorites) to 41% (for one stone of the CO Ornans). Notably, we found significant differences in porosity between the oxidized and reduced CV subgroups, with the porosities of CV_o averaging approximately 20% and CV_r porosities approximately 4%. Overall, porosities of carbonaceous chondrite falls trend with petrographic type, from type 1 (CI) near 35%, type 2 (CM, CR) averaging 23%, type 3 (CV, CO) 21%, to type 4 (CK and some CO) averaging 15%. There is also a significant decrease in porosity between meteorites of shock stage S1 and those of S2, indicative of shock compression.     

The annual period of the Earth’s seismic activity for 1964–2007

The catalog of the United States National Earthquake Information Center (NEIC, 2007) was used for a Fourier analysis of planetary seismic activity from 1964 to 2007 (401219 earthquakes with M ≥ 3 and hypocenter depths H ≥ 1 km) for the Northern Hemisphere (248291 events) and for the Southern Hemisphere (152928 events). The annual periodicity of weak earthquakes (M < 5.0) was verified with a high degree of reliability. All regularities (depending on the geographic latitude, hypocenter depths, and north-south asymmetry) revealed earlier (in 1964–1990) for this period are shown to exist for the period of 1964–2007.     

Main belt binary asteroidal systems with eccentric mutual orbits

Using 8-10-m class telescopes and their Adaptive Optics (AO) systems, we conducted a long-term adaptive optics campaign initiated in 2003 focusing on four binary asteroid systems: (130) Elektra, (283) Emma, (379) Huenna, and (3749) Balam. The analysis of these data confirms the presence of their asteroidal satellite. We did not detect any additional satellite around these systems even though we have the capability of detecting a loosely-bound fragment (located at 1/4×RHill) ∼40 times smaller in diameter than the primary. The orbits derived for their satellites display significant eccentricity, ranging from 0.1 to 0.9, suggesting a different origin. Based on AO size estimate, we show that (130) Elektra and (283) Emma, G-type and P-type asteroids, respectively, have a significant porosity (30-60% considering CI-CO meteorites as analogs) and their satellite's eccentricities (e∼0.1) are possibly due to excitation by tidal effects. (379) Huenna and (3749) Balam, two loosely bound binary systems, are most likely formed by mutual capture. (3749) Balam's possible high bulk density is similar to (433) Eros, another S-type asteroid, and should be poorly fractured as well. (379) Huenna seems to display both characteristics: the moonlet orbits far away from the primary in term of stability (20%×RHill), but the primary's porosity is significant (30-60%).